Magzilla was a doom, stoner, and sludge metal band from São Paulo, Brazil, active from 2013 until splitting up in 2017. The quartet — featuring Guilherme Foresti on vocals and guitar, Pedro Alves on guitar, Joe Borges on bass, and Leandro Furini on drums — released two records: The Oath in March 2016 and a self-titled album in July 2017.

Monje is a stoner/doom metal band from Buenos Aires, active since 2016, featuring guitarist Diego Petullo, vocalist Matias Ibañez, bassist Lucas Scardamaglia, and drummer Diego Hernandez. The band has released three studio albums — Monje (2018), Druga Dimenzija (2020), and Culto al Fin de los Tiempos (2023) — alongside a live album, Igual de Macabro: Live Bunker (2022). Their later work incorporates dissonant harmonies, blast beats, and black and death metal influences alongside the core doom sound.

Mono Histeria is a Curitiba outfit blending progressive, doom, and stoner metal into a dense, riff-driven sound. The band released "Volume 1" in 2022 and has tracks such as "Instinto" and "Primata" available on streaming platforms, pointing toward a sound influenced by the heavier end of the psychedelic and doom rock spectrum.

Monster Coyote were a power trio who built a following in the South American stoner/sludge underground with their debut album The Howling (2012) and the follow-up Neckbreaker (2015), the latter earning positive notices beyond the region. Active until around 2018, the band performed at major Brazilian festivals including Festival DoSol and toured across South America before splitting up.

Mordor Truckers deal in slow-burning, fuzz-heavy stoner doom with a psychedelic edge, built around the guitar work of Manuel Ceballos and a tight rhythm section driven by drummer Brendan Bazzi. Their 2023 EP "Nowhere" — recorded at Wecando Music studio in Joinville — features the tracks "Ammit" and "Mindless," showcasing the band's taste for heavy, hypnotic grooves and atmospheric heaviness.

Mudness is a stoner-doom trio featuring Renan Casarin on guitar and vocals, Fernando Dal Bó on bass, and Pedro Silvano on drums. Their 2023 self-titled debut, recorded at Célula Showcase studios in Florianópolis and produced by Leandro Lazzarotto, delivers seven tracks of heavy, riff-driven doom that circles themes of human fragility and social decay.

Mörmo is a stoner/doom metal trio from La Plata, Argentina, formed in 2018, consisting of Gonzalo Soria on guitar, vocals, and synthesizers, Nicolas Reggiardo on bass and synthesizers, and Rodrigo Carlos on drums. The band released their debut demo Siluetas in August 2018, and followed it with the full-length Nueva razón in February 2023, recorded at Estudios Mirifico in La Plata and mastered by Gonzalo Villagra at Estudios Audion.